This invention pertains generally to the art of drainage systems. Specifically, the invention pertains to a method for repairing a drainage system.
The invention is particularly applicable to the repair of drainage systems that are accidentally or intentionally disrupted or damaged during excavation to gain access to a damaged area of a foundation wall. The invention will be described with particular reference to that environment. It will be appreciated, however, that the invention has broader application and may be advantageously employed to repair any drainage system where the function thereof is jeopardized because the earth or material providing underlying support to the system has been disturbed or has become unstable.
The foundation walls of many buildings are constructed from hollow concrete or cinder blocks. While these materials are inexpensive, they are also disadvantageous because they are porous and permit water and moisture to pass from the exterior of the building to its interior. The seepage of water or liquid through the foundation of a building is obviously undesirable because it adversely affects the comfort of occupants therein and because seepage may result in the weakening of the foundation itself. As such, much effort has been expended to develop ways to prevent the seepage of water through foundations of structures. Such effort has resulted in the development of drain tiles and other drainage systems for eliminating or reducing the accumulation of water in the vicinity of foundation walls.
Known drainage systems frequently take the form of subterranean drain tiles disposed around the outer perimeter of the foundation. These drain tiles typically comprise a pipe that is provided with a number of apertures therein to permit ingress of water from the surrounding soil. Typically, the drain tiles are disposed in a gravel bed to improve their ability to accumulate water from the surrounding area. Water entering the drain tile is conveyed to a remote location away from the building. One known drainage system is disclosed in U.S. Pat. No. 4,538,386, the subject matter of which is incorporated herein in its entirety by reference. That system comprises two sets of drain tiles, one located on the exterior of a foundation wall, and one located on the interior of the foundation wall.
Often, especially in areas where ground shifting is common, foundation walls will develop cracks, bowing or other damage which may require that a portion of the wall be unearthed to expose the damaged area for repairs. In this sense, the aforementioned prior art drainage systems are problematic because they interfere with excavation required to gain access to the damaged area of the foundation. It is usually not feasible to leave the drainage system intact while attempting to excavate the earth in the vicinity of the damaged wall area. Instead, a section of the drainage system is exposed and removed and the earth beneath it excavated so that repair personnel and equipment may have access to the damaged area of the foundation.
After repairs are made to the damaged wall, the earth and the removed section of the drainage system are replaced. Often, in prior art repair methods, settling of the newly replaced earth beneath the drainage system will result in a section of the replaced drainage system being inadequately supported. This, in turn, may result in a sagging and breakage of the drain tiles, thereby impairing the ability of the drainage system to convey water away from the foundation.
One solution to the aforementioned problem is to refill the excavated area with gravel instead of the original earth. Gravel is less prone to settling, but its presence may result in the undesirable accumulation of water in the area near the foundation wall. It would, therefore, be advantageous to provide a repair method that eliminates the aforementioned problems. Namely, it would be desirable to provide a repair system that provides adequate support to the drainage system, is immune or less susceptible to the adverse consequences of ground settling, and does not result in the undesirable accumulation of water near the foundation.
Accordingly, it has been considered desirable to develop a new and improved method for repairing a drainage system which would overcome the foregoing difficulties, meet the above-stated needs and provide better and more advantageous results.